1. Muon Recording Studies and Progress for the MICE Tracker
Tracker Data Readout Basics
Progress in Increasing Fraction of Muons Tracker Can Record
Determination of Recordable Muons as Functions of Digitization Time and Buffer Level
Plans and Outlook

2. Tracker Data Readout Basics
16 Analog Front End II t (AFE-IIt) boards
(‘t’ stands for time)
Input: Analog charge signals from 512 channels
Output:
- Digital hit pattern of 512 channels
- 512 charge amplitudes
- 512 time amplitudes
Each board contains sixteen 32-channel Trigger and Pipeline (TriP-t) chips.
Data from all 16 chips processed in parallel
Within each chip, 32 channels processed in series
DFPGA
X 4 …
AFPGA
AFPGA
X 4 …
X 4 …
ADC
ADC
ADC
ADC
TriP-t
TriP-t
TriP-t
TriP-t
X 4 …
Data from VLPCs
1/4 of AFE-IIt board

3. Muon Recording Increase number of recorded muons by
With D0 configuration and 600 kHz muon rate, AFE-IIt boards can record about 136 kHz
Increase number of recorded muons by
Decreasing digitization time
Zero suppression
Have TriP-t pipeline collect data during digitization
Remove unnecessary setup cycles
Implementing TriP-t analog buffer
Digitization time ≠ dead time.

4. Muon Recording
Digitization of analog charge and time data limits the fraction of muons the tracker will record.
Primary efforts in tracker firmware development have been to reduce time to digitize 32 channels of each TriP-t chip through zero suppression.
Have performed a detailed study of how many muons the tracker can record.

5. Reducing Digitization Time
Assumed muon rate is 600 kHz for average time between muons of 1667 ns.
Clock period taken as 18 ns
Assume 2 out of 32 channels of TriP-t have charge data above threshold
~ 5724 ns: D0 implementation
~ 5670 ns: Adjust for shorter ISIS bucket period
4536 ns: TriP-t pipeline collect data during digitization
2376 ns: Zero-suppress 30 of 32 TriP-t channels
1836 ns: Reduce zero-suppression time from 2 to 1 cycle.
1566 ns: Remove cycles from set-up processes.
We are now starting to reduce the dead time so that it’s comparable to the
average time between muons.

6. Implementing Buffer x x x x
TriP-t chips have 4-level analog buffers which have not been implemented nor tested.
Using one level of buffer greatly increases fraction of muons recorded.
Example: x x x 1 2 3 4 5 6 7
4 of 7 muons
recorded
No Buffer 1 3 4 7 x 1 2 3 4 5 6 7
6 of 7 muons
recorded
1-level Buffer 1 2 3 4 5 7

7. 600 kHz Muon Rate 4-level Buffering 3-level Buffering
No Buffering
(Digitization Time)-1 = 600 kHz
1000
2000
3000
4000
0.2
0.4
0.6
0.8
1.0
Fraction of
Recorded Muons
Digitization Time (ns)

8. Where we were. 600 kHz Muon Rate (Digitization time ~ 5600 ns)
4-level Buffering
3-level Buffering
2-level Buffering
600 kHz Muon Rate
1-level Buffering
No Buffering
(Digitization Time)-1 = 600 kHz
1000
2000
3000
4000
0.2
0.4
0.6
0.8
1.0
Fraction of
Recorded Muons
Where we were.
(Digitization time ~ 5600 ns)
Digitization Time (ns)

9. Where we are. 600 kHz Muon Rate 4-level Buffering 3-level Buffering
No Buffering
(Digitization Time)-1 = 600 kHz
1000
2000
3000
4000
0.2
0.4
0.6
0.8
1.0
Where we are.
Fraction of
Recorded Muons
Digitization Time (ns)

10. Where we’d like to be. 600 kHz Muon Rate 4-level Buffering
No Buffering
(Digitization Time)-1 = 600 kHz
1000
2000
3000
4000
0.2
0.4
0.6
0.8
1.0
Where we’d like to be.
Fraction of
Recorded Muons
Digitization Time (ns)

11. Plans and Outlook
Test digitization, buffering, and firmware with TriP-t chips and AFE-IIt boards.
More about this in next talk…